let array = []
const arr = ['[object Object]:totalRsize:1649932049','[object Object]:totalRsize:1649926940','[object Object]:totalRsize:1649925233'];

arr.forEach(data => {
  const string = data.split(':');
  const data1 = string.slice(0,1);
  array = array.concat(data1);
  // array = array.concat(data);
})
// for (let i = 0; i < arr.length; i++) {
//   array = array.concat(arr[i]);
// }
for (let i = 0; i < array.length; i++) {
  console.log('domain:' + array[i]);
}
// console.log(array);